Percussive tool



Dec. 4, 1934.

W. A. SMITH. JR

PERCUS S IVE TOOL Filed April 19, 1934 Ilhll' In 314% Q I 4 15 18 5 16 Hllli 30 .31 W12. AImiZ/I Jn INVENTOR A TTORNE Y Patented Dec. 4, 1934 1.982,"?011 PERoUssIvE 'rooL Corporation, Virginia New York, N. Y., a corporation of Application April 19, 1934','seia1s0. 721,278

1 Claim.

This invention relates to percussive tools and more particularly to an oiling or lubricating structure for fluid actuated rock drills.

An object of the invention is to provide a lubricating system for rock drills or the like, which will supply the necessary lubricating oil to the various working parts of the drill, utilizing the back pressure of the operating pressure fluid to distribute the oil to the various surfaces requiring lubrication.

With these and other objects in view as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawing, showing a percussive tool of the preferred form, and the features forming the invention will be specifically pointed out in the claim.

In the drawing:

Fig. 1 is a longitudinal section through a percussive tool showing the lubricating system applied thereto.

Fig. 2 is a cross section taken on the line 2-2 of Fig. 1.

Referring more particularly to the drawing, the improved percussive tool of the hammer piston type may be of any approved form and comprises the cylinder 1 in which the piston 2 is reciprocated by means of air or other suitable fluid under pressure. through the throttle valve 3 which throttle valve controls the initial entrance of the pressure fluid into the tool. The throttle valve 3 is located in the back head 4 and the pressure fluid passes 5 from the throttle valve into the annular channel 5 from which it passes through suitable ports and passages into the valve chest 6. The valve 7 in the valve chest 6 controls the distribution of the pressure fluid and consequently controls the reciprocation of the hammer piston 2. The hammer piston 2 has a forwardly extending reduced projection 8 formed thereon which is fluted as shown at 9 in the usual manner. The fluted forward end or extension 8 of the piston 2 travels in the front head washer 10, removable protective bushing 11 therein, and strikes the drill steel 12 which is carried by the chuck mechanism 13 for operating the drill steel.

The front cylinder washer has an oil reservoir 14 therein which may be filled with any suitable type of oil or lubricant in any approved manner. The back plate 15 has an annular groove 16 formed in its periphery which has communication through a port 17 with the pressure channel 5 The pressure fluid enters the rock drill so that air under pressure may pass into the annular groove 16 and out through the port 18 into the passage 19, when the throttle valve 3 is open. The air under pressure passes from the passageway 19 in the cylinder 1 through the port 20 in 6 the cylinder, port 21 in the front cylinder washer 10 into the annular space 22 formed by flats cut on the surface of the bushing 11. From the annular space 22 the air under pressure enters the reservoir 14 through suitable ports 23 formed in the front cylinder washer so that when the throttle valve 3 is open the oil in the reservoir 14 will be under pressure. When the throttle valve 3 is closed the passage of air under pressure to the reservoir will naturally be out ofi and the built-up pressure in the reservoir 14 will cause the pressure fluid to flow backwards from the reservoir 14 through the ports 23'space 22, ports 21 and 20, passage 19 port 18 into the annular groove 16 carrying with it fine particles of oil. When the throttle valve is again opened the fine particles of oil deposited in the annular groove 16 will be forced by the pressure fluid through the port or passage 25 into the valve chest 6 where it will serve to lubricate the working surfaces of the valve as well as working surfaces of the Paullin ratchet structure 26 which is of approved construction used in various approved types of rock drills.

When the pressure fluid again passes downwardly through the passage 19 and through the ports 20 and 21 into the annular space 22 it will force the oil which has entered the annular space 22 by the back pressure from the reservoir 14 downwardly through the space 27 formed by flats on the bushing 11 and across into the spiral groove 28 formed in certain surfaces of the chuck structure 13 for delivering oil to the various working surfaces of the chuck structure. As shown in Fig. 1 of the drawing the spiral groove 28 opens;

through suitable port 29 into the space 30 in the chuck mechanism and out from the space 30 through the ports 31 into the spiral or diagonal groove 32; thus, all of the wear surfaces of the chuck mechanism will be sufficiently lubricated.

From the foregoing description taken in connection with the accompanying drawing, it will be apparent that, when the pneumatic or percussive tool is operating, the oil in the reservoir 14 will be under pressure which pressure is relieved when the throttle is closed, allowing the built-up pressure in the reservoir to flow backwards through the various ports and passages and carry oil with it. Then when the throttle Valve is again opened the oil carried into the various ports and passages will be forced by the pressure of the pressure fluid through other passages, grooves and the like to the various Working surfaces of the drill thereby providing efiicient lubrication to the various parts without delivering excessive oil thereto,

It willibe understood that the'invention is not to be limited to the specific construction or arrangement of parts shown, but that these-maybe W modified widely within the invention as definedby the claim.

What is claimed is: s

In a percussive tool, the combination, .of a cylinder, a throttle valve, ,a valve chest, ajfront cylinder washer having an .oilreservoir therein, a bushing in said washer, a back head having a pressure fluid channel therein, a back plate having an annular groove in its outer surface, said back plate having a port opening into said channel and said groove to supply pressure fluid to the groove, said bushing having a port cut away to form an annular space, ports and passages in ,said back vhead,. cylinder and washer to permit pressure fluid-to fiow from said groove into the annular space in said washer, ports in the washer between said annular space and oil reservoir .whereby fluid under pressure may flow into said reservoir when said throttle is open and when ilsaid throttle is closed the pressure of fluid into reservoirwill flowback and carry oil into said annular space andsaid annular groove, for distribution to working parts of the drill upon reopening of the :throttle.

' WVILLIAM A. SMITH, JR. 

